Apple shares had been trading up 1.5 percent at $87.92 before moving sharply lower. The stock then recovered to trade down about half a percent at $86.15 by mid-afternoon.

"The main reason why Apple shares have sold off midday is that a website reported that Steve Jobs health is getting worse, citing an unidentified source," said William Lefkowitz, an options strategist at brokerage firm vFinance Investments.

"However, this is not the first time Steve Jobs health has come into question. In the past, this has created large fluctuations in Apple stock," he said.

It's the latest resurgence of persistent concerns about the health of Apple's CEO, who underwent surgery for pancreatic cancer four years ago.

Worries surfaced when Jobs appeared dramatically thinner at the company's annual developers' conference in June, sparking debate about complications from the surgery or a reappearance of his cancer. Apple said at the time that Jobs had been fighting a "common bug" and was taking antibiotics.

One reason the rumors persist is because bloggers and industry watchers continue to point to the fact that dragged its heels when it comes to admitting that Jobs was sick: His October 2003 cancer diagnosis hadn't been disclosed until after the removal of a pancreatic tumor.